An obituary described him as an "anthropologist who gave up scholarly detachment to fight for the rights of native peoples."[1] He never married and was survived by his parents and brother. He died of a brain tumor, at 53 years of age, in Oxford, England, where he made his home after 1992.

Posey's switch from entomology to anthropology was due to his friendship with anthropology professor William G. Haag at Louisiana State University. This is explained in a memorial by Posey.[2]

Even after his move to anthropology, Posey did not cut his ties with entomology. At the University of Georgia, he was a close associate of entomology professor Murray S. Blum. Years afterward, he continued to research the ethnobiology of insects, a field he termed "ethnoentomology" in his 1979 doctoral thesis.

After his graduate studies, Posey returned to Brazil in 1982, as a professor in the Department of Biology at the Federal University of Maranhão in São Luís, then reorganized under the chairmanship of geneticist Dr. Warwick E. Kerr. He mounted an interdisciplinary ethnobiological research project, called the Kayapó Project, that would eventually involve over 30 specialists in fields such as agronomy, botany, entomology, plant genetics, astronomy, soil sciences, human geography, anthropology, and linguistics. To document the extensive traditional biological knowledge of the Kayapó Indians, Posey and collaborators spent months in the field with Kayapó specialists such as chiefs Uté, Toto-i, Kanhunk, and Paiakan. Pajés Beptopup and Kwyre-ka also offered their experience. Many conferences with scientific and indigenous project participants served to disseminate project results, especially at Brazilian scientific conclaves.

The Kayapó Project continued when Posey relocated in 1986 to the Goeldi Museum in Belém, Brazil, at the invitation of museum director Dr. Guilherme M. de La Penha. In 1988 he organized the First International Congress of Ethnobiology, in Belém, during which the Kayapó Project and its results were highlighted.

Although the term "ethnobiology" had been used in the past for a different idea, Posey adopted this for his study of indigenous and folk knowledge about plants, animals, and ecosystems. To designate other areas of indigenous and folk knowledge, the term "ethnoscience" can be used in an analogous manner.

In the past, anthropology had been wed to biology in the unholy union of biological determinism, in which Man is treated wholly without culture or the ability to learn. Posey reputiated this view and dared to see indigenous and folk societies as the inheritors of a vast corpus of useful knowledge for the sustainable utilization and management of natural resources. As can be seen in his review of Diamond's best-seller Guns, Germs and Steel: The Fates of Human Societies in 1999, Posey would have biological determinism laid to rest. After all, where can one find human groups without culture?

For ethnobiology to be scientific, testable hypotheses are generated from information offered by indigenous and folk informants. The emic-etic filter has to be respected, and a decoding of traditional knowledge is necessary to bridge the two cultures.

Participant-observation in the field with indigenous and traditional communities was always part of Posey's work plan.

Interviews with informants were always unstructured and conducted according to the generative method, specifically designed not to elicit information offered in support of researchers' perceived biases.

Do the Kayapó Indians manage their natural resources? Do they plant forest islands in the savanna? Do they recognize eco-zones and know what resources are to be found in each? Is their agriculture sustainable? Their hunting? What about their medicine? Does what they know constitute a science?

In his activism, Posey incurred opposition not only from those who would exploit natural resources belonging to Indians but also from scientists and academics who were callous in their disregard for indigenous intellectual property rights. One Brazilian weekly news magazine, Veja, referred to him as a "gigolo of the Indians" for his defense of Indians' human and civil rights.

Posey's support for indigenous peoples brought him into conflict with the Brazilian government in 1987, when Paiakan and Kube-l, two young Kayapó leaders he was accompanying in Washington, D.C., complained to World Bank officials of a planned hydro-electric dam on the Xingu River that would flood Indian lands. The threat of criminal prosecution from the federal government against Posey and the Kayapó chiefs, for interfering in Brazilian foreign affairs, caused a public outcry both in Brazil and abroad.

In February 1989, Darrell helped organize the "First Meeting of the Indigenous Peoples of the Xingu", the first joint meeting of Amazonian tribes to protest the destruction of the forest, in Altamira, Pará. This event focussed on hydro-electric dams on the Xingu River and caused these ecologically disastrous projects to be cancelled or at least reformulated. In 2008, however, these once-discarded projects are again being proposed by the Brazilian government, with slightly different packaging.

In 1992, Posey was the main organizer of the Earth Parliament, a parallel event at the United Nations' Rio de Janeiro Conference on the Environment (Rio Earth Summit), aimed at valuing indigenous knowledge and rights. The Earth Parliament was a 15-day assembly of indigenous and minority groups held during the 1992 Earth Summit.

Like collective rights to land, Indians and other traditional societies have collective intellectual property rights (IPR) to their knowledge. Posey championed the cause of indigenous and folk intellectual property rights during the last decade of his life.

Western society has appropriated indigenous and traditional knowledge without recompensation or even recognition. Posey questioned whether scientific research, even of the most disinterested sort, might not lead to the violation of indigenous intellectual property rights or bio-piracy.

Leading anthropologists, biologists, chemists, sociologists and representatives of several indigenous populations met in to discuss common concerns at the First International Congress of Ethnobiology and to found International Society of ethnobiology. Major concerns outlined by conference contributors were the study of the ways that indigenous and rural populations uniquely perceive, utilize, and manage their natural resources and the development of programs that will guarantee the preservation of vital biological and cultural diversity. This declaration was articulated.

As ethnobiologists, we are alarmed that: SINCE

Tropical forests and other fragile ecosystems are disappearing;

Many species, both plant and animal, are threatened with extinction;

Indigenous cultures around the world are being disrupted and destroyed.

AND GIVEN

That economic, agricultural and health conditions of people are dependent on these resources;

That native people have been stewards of 95% of the world's genetic resources, and

That there is an inextricable link between cultural and biological diversity.

WE, MEMBERS OF THE INTERNATIONAL SOCIETY OF ETHNOBIOLOGY STRONGLY URGE ACTIONS AS FOLLOWS:

Henceforth, a substantial proportion of development aid must be covered to efforts aimed at ehnobiological inventory, conservation, and management programs;

Mechanisms be established by which indigenous specialists are recognized as proper Authorities and are consulted in all programs affecting them, their resources, and their environments;

All other inalienable human rights be recognized and guaranteed, including cultural and linguistic identity;

Procedures must be developed to compensate native peoples for the utilization of their knowledge and their biological resources;

Educational programs must be implemented to alert the global community to the value of ethnobiological knowledge for human well-being;

All medical programs include the recognition of and respect for traditional healers and the incorporation of traditional health practices that enhance the health status of these populations;

Ethnobiologists make available the results of their research to the native peoples with whom they have worked, especially including dissemination in the native language;

Exchange of information should be promoted among indigenous and rural peoples regarding conservation, management, and sustainable utilization of resources."

Posey was a full researcher ("Pesquisador Titular") for the Brazilian National Council for Science and Technology at the Goeldi Museum, Belém, Brazil. He was Director of the Programme for Traditional Resource Rights of the Oxford Centre for the Environment, Ethics and Society and a Fellow of Linacre College, at the University of Oxford. He was Founding President of the International Society for Ethnobiology and was President of the Global Coalition for Bio-Cultural Diversity, under whose auspices he founded the Working Group on Traditional Resource Rights which he coordinated. He was the first recipient of the Sierra Club's "Chico Mendes Award for Outstanding Bravery in Defense of the Environment", and in 1993 he received the United NationsGlobal 500 Award for "Outstanding Achievement in Service to the Environment."

He had few formal students in Brazil or elsewhere, but his impact as a teacher is remembered by many who later became ethnobiologists. He presented many talks in Brazil and other countries, and his work was featured in several films and videos.

The International Society of Ethnobiology (ISEB) created the "Darrel Posey Fellowship" in order to "promote understanding of peoples' complex and dynamic relationship with their environment, and supports indigenous peoples and local communities working to sustainably manage, and security rights to, their environments and resources. The Darrell Posey fellowship for ethnoecology and traditional resource rights was launched in 2004 with a grant from the Christensen Fund, and is administrated by the International Society of Ethnobiology, of which Darrell Posey was a founder.".[4]

The June 2008 11th International Congress of Ethnobiology in Cusco, Peru, will explicitly explore the Darrell A. Posey legacy in a session titled "Ethnobiology and Traditional Resource Rights: Darrell Posey's Legacy." This session will celebrate Darrell Posey's many contributions and influences in the field of ethnobiology over the past several decades, both direct and indirect.[5]

When Western scientists and other academics listen respectfully and learn at the feet of indigenous and traditional leaders, Posey's legacy will become reality.

1988. Without Borders, documentary film made for the United Nations on native peoples; CNN Productions (USA); Barbara Pyle, producer.

1988. Jungle Pharmacy, documentary film made for TV Trust for the Environment, Central TV (Britain) on medicinal plants used by native peoples; Herbert Girardet, producer.

1989. Xingú Encounter, a documentary film about the First Encounter of Indian Peoples in the Amazon, Floresta Films. Neville d'Almeida Director; D. A. Posey, text & narration.

1990. Kayapó Knowledge and the Future of the Amazon, a documentary film about the educational activities and aspects of the ethnobiological research project with the Kayapó Indians, De Campos Produçóes, Belém, Pará; text, narration, editing assistant and co-direction/ production.

1990. Altamira and After, a documentary of the Altamira Encounter and the subsequent activities of the indigenous groups of the Amazon in defense of their native lands and resources, De Campos Produções, Belém, Pará; text, narration, assistant editing and co-production.

1991. The Institute for Ethnobiology of the Amazon—INEA, a documentary about applied ethnobiological research in the Belém-based institute; De Campos Produções, Belém, Pará; text, narration, assistant editing and co-production.

1991. Natural Products and Green Consumerism, a film about "selling the tropical forest" and the problems that result; De Campos Produções, Belém, Pará; text, narration, assistant editing and co-production.

1991. Letter to the Kayapó, a film about the dangers of logging to indigenous peoples, and especially the Kayapó; Footprint Films, London; technical advisor.

Posey, D. A. (1996). Equitable Sharing of Benefits: International Instruments for the Protection of Community Intellectual Property and Traditional Resource Rights . The Hague: International Union for the Conservation of Nature/UNA, International Books.

Posey, D. A. (1984). A preliminary report on diversified management of the tropical forest by the Kayapó Indians of the Brazilian Amazon. In G. Prance (Ed.), Advances in Economic Botany (Vol. 1, pp. 112–116). New York: The New York Botanical Garden.

Posey, D. A. (1986). Concepts of health, illness, curing and death, in relation to medicinal plants and the appearance of the Messianic King on the Island of Lençois, Maranhão, Brazil. In E. Parker (Ed.), The Amazon Caboclo: Historical and Contemporary Perspectives (pp. 279–313). Williamsburg, Virginia: College of William and Mary.

Posey, D. A. (1986). Hypothesis generation and testing in ethnobiology and ethnoentomology: the "intellectual bridge" between science and cultures. In Proceedings of the 10th International Congress of the International Union for the Study of Social Insects (18–22 August 1986). Munich: Springer Verlag.

Posey, D. A. (1990). The application of ethnobiology in the conservation of dwindling natural resources: lost knowledge or options for the survival of the planet. In D. A. Posey & W. L. Overal (Eds.), Ethnobiology: Implications and Applications. Proceedings for the First International Congress of Ethnobiology (pp. 47–61). Belém, Brazil: Museu Paraense Emílio Goeldi.

Posey, D. A. (1991). Importance of semi-domesticated species in post-contact Amazonia: effects of Kayapó Indian dispersal of flora and fauna of the region. In Résumés des Communications, International Symposium on Food and Nutrition in the Tropical Forest: Biocultural Interactions and Applications to Development. Paris: UNESCO.

Posey, D. A. (1991). Intellectual property rights for native peoples: a Pandora's box for those seeking alternatives. In Proceedings of the 8th International Federation of Organic Agricultural Movements. Budapest: IFOAM.

Posey, D. A. (1992). Indigenous peoples and the conservation of biodiversity. In Common Vision: Program Report (pp. 14–16).

Posey, D. A. (1992). Interpreting and applying the "reality" of indigenous concepts: what is necessary to learn from the natives? In K. H. Redford & C. Padoch (Eds.), Conservation of Neotropical Forests: working from traditional resource use (pp. 21–34). New York: Columbia University Press. ISBN 0-231-07603-7

Posey, D. A. (1992). People of the fallows: a historical ecology of foraging in lowland South America. In K. H. Redford & C. Padoch (Eds.), Conservation of Neotropical Forests: working from traditional resource use (pp. 21–34). New York: Columbia University Press. ISBN 0-231-07603-7

Posey, D. A. (1993). Indigenous knowledge in the conservation and use of world forests. In K. Ramikrisha & G. Woodwell (Eds.), World Forests for the Future: Their Use and Conservation (pp. 59–77). New Haven & London: Yale University Press.

Posey, D. A. (1993). Intellectual property rights and just compensation for indigenous knowledge. In M. Bothe, T. Kurzidem & C. Schmidt (Eds.), Amazonia and Siberia: Legal Aspects of the Preservation of the Environment and Development in the Last Open Spaces. International Environmental Law and Policy Series. Holland: Graham & Trotman/Martinus Nijhoff.

Posey, D. A. (1994). Environmental and social implications of pre- and postcontact situations on Brazilian Indians: the Kayapó and a new Amazonian synthesis. In A. C. Roosevelt (Ed.), Amazonian Indians from Prehistory to the Present: Anthropological Perspectives (pp. 271–286). Tucson: University of Arizona Press. ISBN 0-8165-1821-1

Posey, D. A. (1997). Can Kayapó management strategies be equitably utilized and applied?: utilizing Amazonian indigenous knowledge in the conservation of biodiversity. In Cross-Cultural Protection of Nature and the Environment. Denmark: Odense University Press.

Posey, D. A. (1998). Traditional ecological knowledge and the "web of life": rediscovering the cultural and spiritual values of biodiversity. In H. Niec (Ed.), Cultural Rights & Wrongs: A Collection of Essays in Commemoration of the 50th Anniversary of the Universal Declaration of Human Rights. Paris: UNESCO & University of Leicester: Institute of Art and Law.

Posey, D. A. (2000). Biodiversity, genetic resources and indigenous peoples in Amazonia: (re)discovering the wealth of traditional resources of native Amazonians. In A. Hall (Ed.), Amazônia at the Crossroads: The Challenge of Sustainable Development (pp. 188–204). London: Institute for Latin American Studies, University of London.

Posey, D. A. (2000). Exploitation of biodiversity and indigenous knowledge in Latin America: challenges to sovereignty and the old order. In C. Cavalcanti (Ed.), The Environment, Sustainable Development and Public Policies: Building Sustainability in Brazil (pp. 186–209). Cheltenham, UK: Edward Elgar Press.

Posey, D. A., & Overal, W. L. (2000). Social insects and the Kayapó Indians of the Brazilian Amazon: indigenous appreciation and nomenclature of biodiversity. In Proceedings of the International Congress of Entomology.